Steering system for an endless track type tractor

ABSTRACT

A steering system for an endless track type tractor having an engine which has a power distribution device for equally distributing the power of the engine to two outputs, a pair of couplings, a pair of torque converters, a pair of transmissions, a pair of bevel gear mechanisms, a pair of lateral shafts, a pair of final reduction gear mechanisms, a lateral shaft engaging clutch, and a hydraulic control device having an oil tank, a hydraulic pump, a pair of direction shifting valves, a pair of speed control valves, a pair of steering control valves, and a lateral shaft engagement control valve for travelling straight, turning right or left by braking one endless track and driving the other endless track or by inversely driving both the endless tracks. Thus, the turning performance of the tractor is improved.

lluited States atet [191 Suzuki 1 Jail. 15, 1974 l l STEERING SYSTEM FOR AN ENDLESS TRACK TYPE TRACTOR [75] lnventor: Mitsuaki Suzuki, Hirakata, Japan [73] Assignee: Kabushiki Kaisha l iomatsu Seisakuslto, Tokyo, Japan [22] Filed: Mar. 28, 1972 [21] Appl. No.: 238,557

Primary Examiner-Kenneth H. Betts Assistant Examiner-JohdA. Peliar" Attorney-James E. Armstrong et a1.

[57] ABSTRACT A steering system for an endless track type tractor having an engine which has a power distribution device for equally distributing the power of the engine to two outputs, a pair of couplings, a pair of torque converters, a pair of transmissions, a pair of bevel gear mechanisms, a pair of lateral shafts, a pair of final reduction gear mechanisms, a lateral shaft engaging clutch, and a hydraulic control device having an oil tank, a hydraulic pump, a pair of direction shifting valves, a pair of speed control valves, a pair of steering control valves, and a lateral shaft engagement control valve for travelling straight, turning right or left by braking one endless track and driving the other endless track or by inversely driving both the endless tracks. Thus, the turning performance of the tractor is improved.

' PAIEMEU 3.785.450

sum 01 or 19 PATENTED JAN 1 SIEIH SHEET '02 0F T9 LEFT 180 72 1s T T ;r 85 510 i 70 7 51 R'GHT I y l 52 PF) 2 1 PF M52 730 I 710 a 73 l 52 REVERSE L FORWARD NEUTRAL iREvERSE MAN MAN T I T T "T 530 540 L .L J. .L l J. 1 .L .1. MAN T MAN T"' T TT TT T TTT TTT TyTT TT T "T 1stsp. 2ndsp.3rclsp. 3rdsp. 2ndsp.1stSp.

i 52 1 Lu] 820 I l 82 I 1T :5 550' 56 H% II H 600 69 1 M T T A 15 Z? BOTH-SIDE TURN -550 55 W fl 61 URN ONE- SIDE T TURN oNE- SIDE TURN STRAIGHT k T A 6H T STRAIGHT 52 52 52 I 580 58 FORWARD :E FORWARD 59 REVERSE REVERSE LATERAL SHAFT PATENTEUJAN 1 51914 LEF T BOTH SIDE TURN REVERSE 5 NE SIDE TURN *STRAIGHT O 5 5 MA STRAIGHT FORWARD REVERSE D m W R O F REVERSE LATERAL SHAFT PAT NTTTSTTN 3.785.450

sum 070T 19 REVERSELITI FoRwARDi WA R D REVERSE T F/G.8 130\ 140 14 -13 1stsp- 2ndsp.3rdsp 3rdsp, Zfldsp, 1stsp. 52 j T T w 120 IA'F 16 12 A ONE-SIDE N N A. r TURN TuRN I T --ONESIDE TURN Y P STRAIGHT STRAIGHT r STRAIGHT 52 58 FORWARD A FFORWARD REVERSE REVERSE LATERAL SHAFT Z! M09 101 --4 L 102 s2 PATENTED JAN 1 5 [974 9 M 2 l U F E mm DIRECTION SHIFTING VALVE SPEED CONTROL VALVE E m S H T TURN ONE-SIDE NE- SIDE TURN STRAIGHT STRAIGHT FORWARD -REV ERSE IN CUT IN l}? LATERAL SHAFT PATENTTTT f 3.785.450

sum 130F19 F/GHB DIRECTION SHIFTING VALVE 3rdsp.2ndsp 1 1 SP.

1 SPEED 83 CONTROL BOTHS|DE 'BO SIDE TURN TTHURN ONE-SIDE ONE -51 DE TURN TURN STRAIGHT STRAIGHT FORWARD FORWARD RE VERSE 59':H[='REVERSE r I IN CUT IN L m l g LATERAL SHAFT PATENTED JAH Y 3, 785.450

' SHEET 1% III 19 FIGJIC DIRECTION 52 Sl-IIFTI PF 01 VALVE 52 T I l" 52 53 3 TT2T T TYT rdsp' ndspm K195? CONTROL VALVE {I[=82-I {11 8311 -U1=8A1II BOTH-SIDE TURN I BOTH-SIDE ONE-SIDE TURN TURN ONE-SIDE STRAIGHT TuRN FORWARD STRAIGHT ARD 58 J [15 REVERSE T I IN CUT IN @III IE IT HID LL I EE LATERAL 31 SHAFT PATENIED I 5 I974 3 785 450 SHEET 15 0F 19 F/GJID DIRECTION SHIFTING VALVE Y 1 T1 -t I Sp CONTROL UI:,82 1 VALVE 83 I II1= 1II BOTHESIDE TU 55 M ONE-SIDE TURN 1N STRAIGHT 52 a BOTH-SIDE TURN FORWARD 3 ONESIDE REVERSE 4 TURN L STRAIGHT I E 58$=--FORWARD I: --REVERSE I L I I I I I I I W I mflifll IN 5i IN OUT IN i v C TL T 94 II |LATERAL SHAFT PATENTED I 5 F974 3. 785.450

sum 15 0F 19 FIG. 72A

DIRECTION 101 SHIFTING 102 PF VALVE SPEED-CONTROL l F; VALVE 84 q %1I III 111 STEERING CONTROL-VALVE 550 5 M v M 550 BOTH-SIDE 55 A TuRN N N ONE- SIDE ONE-SIDE TURN A R E 1 E 5U TuRN STRAIGHT H STRAIGHT FORWARD REVERSE ENGAGEMENT CONTROL VALVE LATERAL SHAFT PATENTEBJAN I 519M FIG. 72B

sum .17 [1F 19" DIRECTION SHIFTING VALVE SPEED-CONTROL VALVE STEERING CONTROL-VALVE B 55 L4 550 %L TURN Q N k 3 T"ONE-SIDE BOTH-SIDE TURN L STRAIGHT A N ONE-SIDE TURN E STRAIGHT M- F FORWARD REVERSE -q a 59 i I l -'--REvERs E.

r ("TNCUT IN I E CUT IN L T LATERAL SHAFT 52 94 A 94 52 ENGAGEMENT s1 CONTROL VALVE LATERAL PATENTEBJAN I 5 I974 SHEET 1a or I DIRECTION FTI NG VALVE REVERSE TTT SPEED CONTROL VALVE TIM TT TT STEERI N G CONTROL- VALVE BOTH sI DE ES TURN O E- SIDE ONE SIDE TURN STRAIGHT TURN STRAIGHT M 4 FORWARD a REVERSE -REVERSE T TNW A Hmv SMHUL L O mm EEN M O L C 2 5 IN CUT IN ERAL SHAF PATENTEDJAH 1 M 1 31785.450

saw 19 HT 19 F/GJZD PF 52 DIRECTION 73 SHIFTING 52 VALVE 102 101 R PF NEUTRA- EVERSE 52 FORWARD T T r.\ 52 4 l SPEED CONTROL W I VALVE 840 STEERING 1143b ---HI=8411I CONTROL'VALVE r M 55 a 550 QLT 5 55 Q ONE-SIDE. M ONE-SIDE TURN E A 3 TURN 52 N STRATGHT P Y STRAIGHT FORWA D A q l FORWARD I 58 REVERSE =%]1 r-'- I I --REVERSE 59o L 59 1 F 1 I 1 E I 5 I I I fi IN CUT IN 1 N cuT IN LATERAL SHAFT 52 940 94 5 EN GAGEMEN T 31 1 CONTROL VALVE LATERAL SHAFT 

1. A steering system foran endless track type tractor having an engine comprising a power distribution device for equally distributing the power of the engine of the tractor to two outputs, a pair of power trains each having a torque converter, a coupling for the power from said power distribution device to said torque converter, a transmission, a lateral output shaft, a bevel gear mechanism having a bevel pinion and a bevel gear for transferring the power from the torque converter through the transmission to said lateral output shaft, and a final recuction gear mechanism having a pinion and a gear for transferring the power from said lateral output shaft to a sprocket for driving the endless track, a lateral shaft engaging clutch for engaging directly the lateral shafts to each other when hydraulically energized and for disengaging the direct coupling of the lateral shafts when hydraulically deenergized, a pair of steering brakes for braking either one lateral shaft to turn the tractor rightwardly or leftwardly when said lateral sahft engagin clutch is disengaged and either one transmission is shifted to neutral position, a hydraulic control device having an oil reservoir, a pair of hydraulic pumps, a pair of forward clutches for engaging the transmission in the forward direction when hydraulically energized, a pair of reverse clutches for engaging the transmission in the reverse direction when hydraulically energized, a pair of direction shifting valves each having forward, neutral and reverse positions for feeding hydraulic fluid from either hydraulic pump to said either forward clutch, for draining the hydraulic fluid, and for feeding hydraulic fluid from either pump to said either said reverse clutch and for draining either said forward clutch, respectively when manually shifted, a pair of first speed clutches for engaging the transmission at first speed, a pair of second speed clutches for engaging the transmission at second speed, or a pair of third speed clutches for engaging the transmission at third speed, a pair of speed control valves each having neutral and first, second or third speed positions for feeding hydraulic fluid from either said hydraulic pump to said oil reservoir, first, second or third speed clutches, respectively when manually operated, a pair of steering control valves each having straight, one-side turn and both-side turn positions for feeding the hydraulic fluid from the hydraulic pump to said forward or reverse clutches, for draining either forward clutch and reverse clutches and for feeding the hydraulic fluid from the hydraulic pump to either forward clutch and for feeding the hydraulic fluid from the pump to one forward clutch and for feeding the hydraulic fluid from the pump to the other reverse clutch when manually operated, and a lateral shaft engagement control valve having straight and turn positions for feeding the hydraulic fluid from the hydraulic pump to said lateral shaft engaging clutch and for draining said lateral shaft engaging clutch when manually operated.
 2. The steering system according to claim 1, further comprising a pressure compensating valve for gathering equally the hydraulic fluid from said pumps to engage the lateral shaft engaging clutch and hydraulically connected at both side ends to said hydraulic pumps, respectively and having a pair of fluid passages formed therein for gathering the hydraulic fluid from said pumps and another pair of fluid passages for flowing the fluid from either pump to the fluid output.
 3. The steEring system according to claim 2, wherein said pressure compensating valve is composed of a lateral shaft engaging clutch pump hydraulically connected to said lateral shaft engagement control valve from said oil reservoir, and a relief valve hydraulically connected to the output of said lateral shaft engaging clutch pump from said oil reservoir for maintaining the hydraulic pressure constant.
 4. The steering system according to claim 1, wherein said lateral shaft engagement control valve is composed of a pair of lateral shaft engagement control valves one of them hydraulically connected at both side ends to said one forward clutch and said other reverse clutch and other of them hydraulically connected at both side ends to said other forward clutch and said reverse clutch, and each having a CUT position at the center and IN positions at both sides of the CUT position for disengaging said lateral engaging clutch and for engaging said lateral engaging clutch respectively.
 5. A steering system at set forth in claim 1, wherein said hydraulic control device comprises a lateral shaft engaging clutch pump and a relief valve for maintaining the hydraulic pressure constant.
 6. A steering system as set forth in claim 5, wherein said hydraulic control device comprises a pair of lateral shaft engagement control valves for engaging said lateral shaft engaging clutch.
 7. A steering system as set forth in claim 5, wherein said hydraulic control device comprises a pair of first steering control valves each having straight and one-side positions, and a pair of second steering control valves each having both-side turn position. 